Technical Field
The present invention relates to an ultrasonic sensor as well as a probe, an electronic apparatus, an ultrasonic imaging apparatus, and the like using the same.
Related Art
Ultrasonic devices for use in ultrasonic diagnostic apparatuses, for example, are commonly known. Ultrasonic devices include a vibration plate. A bottom electrode is laminated on the vibration plate. A piezoelectric body is laminated on the bottom electrode. A top electrode is laminated on the piezoelectric body. The piezoelectric body extends to the outside of the outline of the bottom electrode, thereby preventing short-circuiting between the top electrode and the bottom electrode.
JP-A-2000-183413 discloses a displacement element. The displacement element includes a piezoelectric element that is laminated on a vibration plate. The ratio of the width of the piezoelectric element to the width of the vibration plate is specified. Thus, optimization of the displacement with respect to the driving voltage is proposed. However, in JP-A-2000-183413, no mention is made of the potential that is output when the vibration plate is displaced. Moreover, the width of the piezoelectric film and the width of the electrode are the same as each other. Therefore, the effect of the width of the bottom electrode with respect to the thickness of the piezoelectric film is not considered at all.